J. Strobel

Noninvasive measurement of the Bayliss effect in retinal autoregulation.

Abstract · Purpose: The Bayliss effect describes the reaction of smooth muscle cells in the arterial wall to changes in blood pressure. A rise in mean arterial blood pressure (MAP) causes an autoregulatory myogenic vessel constriction by smooth muscle cells in the arterial wall. The responsiveness of retinal vessels to changes in MAP were analyzed using the Retinal Vessel Analyzer (RVA). · Methods: Continuous measurement of retinal arterial vessels was performed in 40 healthy volunteers (age 18–56 years.) over a 9-min period. After a 3-min baseline measurement (phase I), isometric exercise caused a rise in MAP over the next 3 min (phase II). During the last 3 min (phase III) recovery was observed. Blood pressure and ECG were documented simultaneously throughout the experiment. · Results: Exercise caused a significant rise of 22.8 (±6.0) mmHg in MAP (phase II vs phase I: P<0.001). Retinal arterioles showed 5.5% (±2.8%) vasoconstriction (P<0.001). During phase III vessel diameters returned to normal, with no difference from phase I (P=0.179). · Conclusion: Noninvasive measurement and quantitative analysis of the Bayliss effect in human retinal vessels by means of the RVA is possible. Analysis of retinal arterial autoregulation may provide valuable insight into pathologic conditions such as diabetic or hypertensive retinopathy.

Optic Edge Design as Long-term Factor for Posterior Capsular Opacification Rates

OBJECTIVE To compare the difference in posterior capsular opacification (PCO) between highly refractive silicone and hydrophobic acrylic foldable intraocular lenses (IOLs) with sharp and round edge designs 3 years after in-the-bag IOL implantation in subjects undergoing bilateral cataract surgery. DESIGN Open-label, prospective, randomized, multicenter clinical trial. PARTICIPANTS Two hundred and eighty-eight patients with bilateral surgery for senile cataract operated in German university clinics, eye hospitals, and private ophthalmic surgical centers (Aachen, Ahaus, Bad Hersfeld, Frankfurt/Main, Jena, Rosenheim, and Sulzbach/Saar). INTERVENTIONS At each center, a highly refractive index silicone IOL with a sharp optic edge (CeeOn) was intraindividually compared either with a high-refractive index silicone IOL with a round optic edge (PhacoFlex) in 108 patients or with an acrylic IOL with a sharp optic edge (AcrySof) in 139 patients. All patients received standard phacoemulsification with IOL implantation in the bag in both eyes from the same surgeon. A morphological evaluation of PCO was performed by the Evaluation of the Posterior Capsule Opacification (EPCO) system 1 to 2 weeks and 11 to 14 and 35 to 37 months after surgery. The blinded digital pictures were evaluated by an independent investigator. Posterior capsular opacification was statistically evaluated by paired comparisons of 3-year cumulative incidences of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser treatment and EPCO scores. MAIN OUTCOME MEASURES Posterior capsular opacification. RESULTS The 3-year cumulative incidences of Nd:YAG laser capsulotomy were 2.1% (CeeOn), compared with 2.1% (AcrySof) (risk difference, 0%; 90% confidence interval, -3.4% to 3.4%), and 5.7% (CeeOn), compared with 17.0% (PhacoFlex) (risk difference, -11.4%; 90% confidence interval, -18.1% to -4.7%). In patients without Nd:YAG laser treatment, medians of the total area EPCO score were 0.0005 (CeeOn) versus 0.0440 (AcrySof) and 0 (CeeOn) versus 0.0700 (PhacoFlex) at 3 years. Functional results, safety, and handling did not significantly differ for the 3 lenses. CONCLUSIONS Our results suggest that modern foldable IOLs have a low incidence of PCO after 3 years. There is less PCO for sharp optic edge designs independent of IOL material.

Posterior capsule opacification after implantation of CeeOn Edge 911A, PhacoFlex SI-40NB, and AcrySof MA60BM lenses One-year results of an intraindividual comparison multicenter study

Purpose: To perform an intraindividual comparison of posterior capsule opacification (PCO) with 2 foldable intraocular lenses (IOLs) and a foldable acrylic IOL 1 year after in‐the‐bag implantation. Settings: Seven German ophthalmology centers. Methods: In an open prospective randomized multicenter study, each center intraindividually compared a high‐refractive‐index, sharp‐edged optic silicone IOL (CeeOn® Edge 911A, Pharmacia) with a high‐refractive‐index, round‐edged optic silicone IOL (PhacoFlex® SI‐40NB, Allergan) or a sharp‐edged optic acrylic IOL (AcrySof® MA60BM, Alcon). Of 288 randomized patients, 247 had standard phacoemulsification with in‐the‐bag IOL implantation in both eyes by the same surgeon. One eye of each patient received a CeeOn Edge IOL and the fellow eye, an AcrySof or PhacoFlex IOL. A morphologic evaluation of PCO was performed using the Evaluation of Posterior Capsule Opacification (EPCO) system 1 to 2 weeks and 11 to 14 months after surgery. The digital pictures were evaluated by an independent investigator who was blind to the type of IOL. Intraindividual differences in EPCO scores were statistically evaluated by a 1‐sided binomial test at an &agr;‐level of 5%. Results: One year after surgery, 127 patients with the AcrySof IOL and 102 patients with the PhacoFlex IOL in the control eye were reexamined. Functional results, safety, and handling were not significantly different between the 3 IOLs. All reexamined eyes had a very low PCO grade. The EPCO values revealed less PCO in eyes with the CeeOn Edge IOL than in eyes with the AcrySof or PhacoFlex IOL, but the difference was not statistically significant. A neodymium:YAG laser capsulotomy was performed in 1 eye with a CeeOn Edge IOL, 1 eye with an AcrySof IOL, and 2 eyes with a PhacoFlex IOL. Conclusions: The EPCO PCO grade was low 1 year after implantation of CeeOn Edge 911A, PhacoFlex SI‐40NB, and AcrySof MA60BM IOLs; there was no statistically significant difference between the IOLs. The impact of IOL material and edge design on PCO development might be relevant in a long‐term follow‐up of this study.

Anterior segment optical coherence tomography for evaluation of changes in anterior chamber angle and depth after intraocular lens implantation in eyes with glaucoma

Purpose. To examine anterior chamber depth (ACD) and anterior chamber angle (ACA) in patients with glaucoma after cataract extraction with an anterior optical coherence tomography (OCT) system. Methods. A new commercially available 1310 nm infrared light anterior segment OCT system was used for anterior chamber evaluation. Sixty patients (n=20 with primary open angle glaucoma [POAG], n=20 with angle closure glaucoma [ACG], and n=20 with no known glaucoma as control group) with a mean age of 68.8±13.9 years undergoing cataract surgery were enrolled. Results. Before cataract surgery, ACD and ACA of the ACG group were significantly lower compared to the POAG and control groups (ACD p<0.005; ACA p<0.005). After cataract extraction, ACD and ACA increased significantly in the ACG group (3.1±0.4 mm vs 1.8±0.2 mm, p<0.005 and 32.3°±7.7° vs 16.0°±4.7°, p<0.005). In the POAG and control groups, ACD and ACA also increased postoperatively, but not as much as in the ACG group. After cataract extraction, IOP decreased significantly in the glaucoma groups (ACG: 15.6±6.1 vs 18.6±5.7 mm Hg, p=0.008; POAG: 16.2±3.4 vs 20.7±8.0 mmHg, p=0.02) and was almost the same in all three groups after surgery (control group after surgery: 15.2±2.8 mmHg). Conclusions. Both ACD and ACA increased significantly after cataract extraction and IOL implantation. IOP reduction after surgery was higher in the glaucoma groups compared to the control group.

Increased content of zinc and iron in human cataractous lenses.

The purpose of the study was to examine the zinc and iron content of human lenses in different types of cataract and to investigate the possible influence of diabetes on the zinc and iron content of the lens. Iron and zinc of 57 human lenses (28 corticonuclear cataracts and 29 mature cataracts with a mean age of 70.6±16.1 and 74.7±11.1 yr, 41 nondiabetics and 16 diabetics) were determined by atomic absorption spectroscopy. The zinc content of human lenses was significantly increased in mature cataracts compared to corticonuclear cataracts (0.51±0.33 vs 0.32±0.20 µmol/g dry mass, p=0.012). The iron content of mature cataracts was also higher than in corticonuclear cataracts (0.11±0.09 vs 0.07±0.05 µmol/g dry mass, p=0.071). Furthermore, a significant increase of the lens zinc content could be observed with increasing lens coloration (light brown 0.33±0.17 vs dark brown 0.52±0.35 µmol/g dry mass, p=0.032). Diabetic patients seem to have both increased zinc and iron contents in the lens compared to nondiabetic subjects (zinc: 0.45±0.42 vs 0.40±0.22 µmol/g dry mass; iron: 0.12±0.10 vs 0.08±0.05 µmol/g dry mass). These data suggest a possible influence of the lens zinc and iron content on the development of lens opacification. Especially advanced forms of cataract and dark brown colored lenses show significantly increased zinc and iron content.

Endogene Endophthalmitis bei schweren Allgemeinerkrankungen

Hintergrund: Die endogene Endophthalmitis bei schweren Allgemeinerkrankungen und reduziertem Allgemeinzustand hat trotz moderner antibakterieller, antimykotischer und operativer Therapie eine äußerst schlechte Prognose.Patienten: Die Studie zeigt den Krankheitsverlauf bei 5 Augen von 4 Patienten mit endogener Endophthalmitis. Das Alter der Patienten lag zwischen 58 und 71 Jahren. Die Zeitspanne zwischen dem Auftreten der ersten Augensymptome und der stationären Aufnahme betrug 1 Woche bis 3 Monate. An Allgemeinerkrankungen waren Endometriumkarzinom, Kolonkarzinom, Korpuskarzinom (mit Bauchfistel) und Pankreasinsuffizienz (mit Subklaviakatheter) sowie Diabetes mellitus bekannt.Ergebnisse: Entsprechend dem Keimnachweis (Candida albicans in 3 Augen, Bakterien in 2 Augen) wurde antibakteriell bzw. antimykotisch lokal, subkonjunktival und systemisch behandelt sowie eine Pars-plana-Vitrektomie und/oder Glaskörperpunktion mit Antibiotika- bzw. Antimykotikaeingabe durchgeführt. Trotzdem lagen abschließend folgende Befunde vor: 1 Auge Enucleatio bulbi, 1 Auge Evisceratio bulbi, 2 Augen Lichtschein, 1 Auge Visus 0,2.Schlußfolgerung: Die Einweisung der Patienten in Kliniken mit einer Abteilung für Glaskörperchirurgie sollte möglichst frühzeitig erfolgen. Nur so ist es möglich, schnell mit einer adäquaten Therapie zu beginnen.Background: In spite of modern antibacterial, antimycotic and operative therapies, endogenous endophthalmitis connected with other severe diseases and an impaired state of health is an eye complication with a very poor prognosis.Patients: The study presents observations about the progress of the endogenous endophthalmitis in five eyes of four patients. The age of the patients ranged from 58 to 71 years. The span between the appearance of the first eye symptoms and hospital treatment amounted to 1 week and 3 months. The general diseases have been diagnosed as endometrium cancer, colon cancer, corpus uteri cancer (with intestinal fistula) and pancreatic insufficiency (with subclavian catheter) as well as diabetes mellitus.Results: In regard to the infections we analyzed (Candida albicans in 3 eyes, bacteria in 2 eyes), very intensive medical treatment was initiated, including antibacterial or antimycotic therapy (local, subconjunctival, intraocular and systemic) as well as pars plana vitrectomy and/or vitreous puncture. Nevertheless, by the end of the clinical attendance, the following statements were established: one-eye enucleation, one-eye evisceration, two eyes perception of light, one eye visual acuity 0.2.Conclusion: The patients should be immediately admitted to a hospital with a department for vitreous surgery. Only with this option is it possible to initiate adequate therapy.

Surgical approach in Terson syndrome : vitreous and retinal findings

Purpose To report some interesting findings in patients with bilateral Terson syndrome. Methods We describe six eyes from three patients with Terson syndrome. Pars plana vitrectomy was performed in one eye twelve weeks, and in four eyes six months after the acute event. In one eye blood was suddenly spontaneously absorbed after four months. Results The four eyes operated six months after injury showed severe complications and final visual acuity was between light perception and 0.6. The eye with surgical attendance twelve weeks after the acute injury had an uneventful course, and final visual acuity was 0.7. Conclusions Because of severe ocular complications and with a view to early rehabilitation, vitrectomy has been recommended for eyes with bilateral Terson syndrome, without spontaneous blood resorption. Surgery should be performed in at least one eye not later than four to eight weeks after the acute injury.

Scattering properties of the retina and the choroids determined from OCT-A-scans

Goal: To determine the coefficient and the anisotropy of scattering as well as the refractive indices in the retina and in the choroid noninvasively in vivo.Methods: The power of coherent reflected light versus fundus depth is recorded in OCT-A-scans. The ratio of refractive indices is derived from the height of the reflection peaks. Providedthat the absorption coefficient is known from fundus reflectometry, the scattering coefficient and anisotropy are calculated from the offset and the slope of the signal behind the reflection peaks on the basis of a single backscattering model.Results: We found scatteringcoefficients of 12/mm (retina) and 27.5/mm (choroid) as well as anisotropy values of 0.97 (retina) and 0.90 (choroid).Discussion: The OCT is usually employed for the measurement of intra-ocular distances. The new technique described here gives the unique opportunity to determine further interesting parameters of single ocular layers. The values given above are in good agreement with in vitro results.

Spektrale Differenzierung in Eigenfluoreszenzbildern des Augenhintergrunds von Patienten mit altersabhängiger Makuladegeneration

ZusammenfassungHintergrundEine veränderte Eigenfluoreszenz des Augenhintergrunds wird gegenwärtig insbesondere im Zusammenhang mit der altersabhängigen Makuladegeneration diskutiert. Zu ihrer richtigen Bewertung sind jedoch weitere Kenntnisse über das chemische Substrat der Fluoreszenz erforderlich.MethodeDie Autofluoreszenz des Augenhintergrunds wurde mit einer Funduskamera beobachtet. Die Anregung erfolgte im blauen Spektralbereich. Zur Aufzeichnung der Fluoreszenz wurde eine 3-Chip-CCD-Farbkamera benutzt. Zum Vergleich wurden die Fluoreszenzspektren von Lipofuszin, A2-E, FAD, NADH2 und AGE mit dem Jenaer Ophthalmospektrometer aufgenommen.ErgebnisseIm Gegensatz zu einem gesunden Fundus zeigen die Autofluoreszenzaufnahmen an Patienten mit AMD deutlich lokalisierbare Areale spektral unterschiedlicher Fluoreszenzemission. Die jeweils gefundenen Emissionsspektren zeigen starke Überlappungen.SchlussfolgerungenDie vorgestellte Technik ermöglicht es, spektrale Unterscheidungen in Bildern der Autofluoreszenz des Augenhintergrunds vorzunehmen. Neben der des Lipofuszins wurde bei Patienten mit nichtexsudativer AMD eine kurzwelligere Fluoreszenz beobachtet.AbstractIntroductionAlterations in the intrinsic ocular fundus fluorescence are under discussion particularly in connection with age-related macular degeneration. However, further knowledge of the chemical substrate of fluorescence is necessary.MethodOcular fundus autofluorescence was observed using a fundus camera. The fluorescence emission was recorded using a 3-chip CCD camera. For comparison, the fluorescence spectra of lipofuscin, A2-E, FAD, NADH2 and AGE’s were recorded by the Jena ophthalmo-spectrometer.ResultsIn contrast to the homogeneous intrinsic fluorescence of a normal fundus, the fluorescence images of patients suffering from AMD showed remarkable local differences. The detected fluorescence spectra showed remarkable overlaps.DiscussionWe introduced a new technique enabling the detection of spectral differences in images of ocular fundus autofluorescence. Besides the fluorescence of lipofuscin, we found a green one in patients suffering from nonexudative AMD.

Vasoconstriction of retinal arterioles with oxygen breathing in diabetic retinopathy

ZusammenfassungHintergrund. Mit dem Retinal-Vessel-Analyser (RVA) ist eine nichtinvasive Online-Untersuchung von retinalen Gefäßdurchmessern möglich.Mittels Atmung von 100% Sauerstoff soll in der vorliegenden Studie die Kontraktilität der retinalen Arteriolen in unterschiedlichen Stadien der diabetischen Retinopathie (RD) untersucht werden. Methodik. Vierzig Patienten mit Diabetes mellitus wurden nach einer 3-minütigen Ausgangsmessung einer 5-minütigen Atemluft mit 100% Sauerstoff ausgesetzt. Mit dem RVA wurde über die gesamte Versuchsdauer eine retinale Arteriole vermessen. Die Personen wurden in 4 Gruppen mit unterschiedlichen Ausprägungen der RD eingeteilt: Gruppe I: keine RD; Gruppe II: milde/mäßige RD;Gruppe III: mäßige/schwere, nicht proliferative RD mit Lasertherapie; Gruppe IV: proliferative RD mit Lasertherapie. Ergebnisse. Gruppe I (n=12) zeigte eine Vasokonstriktion von 6,2 (±4,0)%.Gruppe II (n=8) von 6,1 (±2,8)% und Gruppe III (n=8) von 6,6 (±4,1)%.Gruppe IV (n=12) zeigte eine Vasodilation +2,5 (±4,7)%. Schlussfolgerung. Bei der Reaktion auf 100%-Sauerstoff-Atmung konnte zwischen den Stadien der nichtproliferativen RD kein signifikanter Unterschied nachgewiesen werden.Beim Auftreten von Proliferationen ist eine Reduktion der Gefäßantwort nachweisbar.AbstractObjectives. The retinal vessel analyzer (RVA) offers the unique opportunity of noninvasive online measurements of retinal vessel diameters. Breathing 100% oxygen is used to test vessel contractility of retinal arterioles in different stages of diabetic retinopathy (DR). Methods. After a 3-min baseline measurement 40 patients with diabetes were exposed to 100% oxygen breathing for a 5-min period.The diameter of a retinal arteriole was measured with the RVA continuously during this time.Subjects were divided into four groups according to different stages of DR.Group I: no RD; group II: mild/moderate RD; group III: moderate/severe nonproliferative RD with laser treatment; group IV: proliferative RD with laser treatment. Results. Group I (n=12) demonstrated a vasoconstriction of 6.2% (±4.0). In group II (n=8) 6.1% (±2.8) and in group III (n=8) 6.6% (±4.1) vasoconstriction was found. Group IV (n=12) presented a vasodilatation of +2.5% (±4,7). Conclusion. No significant differences could be found in the vasoreaction to 100% oxygen breathing in different stages of nonproliferative RD.However, a significant reduction could be demonstrated in proliferative DR with this method.